Breastfeeding by a mother taking cyclosporine for nephrotic syndrome

BACKGROUND: Cyclosporine is widely used for immunosuppressive treatment of various systematic and local autoimmune diseases. Breastfeeding is conventionally contraindicated when treating with cyclosporine due to its excretion into breast milk, which may cause immune suppression of exposed infants and affect infants` growth. A few cases have tested cyclosporine levels in random breast milk samples and concluded the infants exposed to safe cyclosporine levels during breastfeeding. Since infants do not maintain a fixed feeding schedule, we monitored cyclosporine levels in breast milk at different times of the day to assess the safety of breast milk for infants throughout the day. CASE PRESENTATION: A 32-year-old dichorionic twin-pregnancy woman had nephrotic syndrome with renal biopsy confirmed type V lupus nephritis for over five years. She was treated only with prednisone 10 mg a day before pregnancy and during early pregnancy. Cyclosporine was added in her regimen from 22 weeks gestation and was adjusted to 225 mg a day from 28 weeks gestation. After parturition, she partially breastfed her twin infants while being treated with cyclosporine 3 mg/kg a day as well as prednisone and hydroxychloroquine sulfate. The cyclosporine level in maternal blood was determined, and several breast milk samples were collected for consecutive 48 h beginning on the ninth day after parturition. The concentration of cyclosporine in breast milk was measured and ranged from 0.443 to 5.307 mcg/L. Both infants grew and developed normally at the three-month follow-up, with no adverse effects observed. The study was conducted at West China Second University Hospital of Sichuan University, started in September 2021, with the consent of the participant and the approval of the ethics committee. CONCLUSION: In this case, cyclosporine levels in breast milk were low at all times of the day. The growth and development of both infants were normal at three months postpartum. Thus, breastfeeding may still be an option for mothers with nephrotic syndrome who are treated with cyclosporine. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13006-022-00514-4.